Christine Testerman
Who I am
My fascination with biology started when I was a young girl. My father, a nuclear physicist, was gardening one spring day and struck and killed a mole. Not wanting to waste an educational opportunity, he brought the mole into the garage and dissected it for my younger brother and me. I was immediately curious about how all the organs worked and wanted to know more. My first ‘scientific’ studies started a few years later when I began colour-breeding experiments with mice. We lived in Minnesota, USA, far from any oceans, so my parents did not have to put up with me playing with sharks, only unusual pets like mice! However, Minnesota is known as the land of 10,000 lakes. Being in and on the water was a big part of my childhood, so it was really no surprise that I was eventually drawn to the sea.
After completing my undergraduate degree in genetics and cell biology, I combined my love of biology with an MBA and went to work in the biotechnology industry in Houston, Texas. During this time I started scuba diving. On my very first dive trip I saw a great hammerhead shark, a spotted eagle ray, and a whale shark that played with my dive buddy and me. As I witnessed the grace and beauty of these animals, my love of and respect for these magnificent predators was born.
Diving headlong into my newfound passion, I became increasingly aware of the dramatic population declines suffered by many shark species due to overfishing and the high demand for shark fins. Such large population decreases created an urgent need to conserve and protect these ecologically important animals. At the same time, molecular genetic technologies developed rapidly and their cost decreased to the point where it became feasible to apply genetic studies to wildlife. Thus, I decided to pursue my PhD in the laboratory of Dr Mahmood Shivji at the Save Our Seas Shark Research Center USA at Nova Southeastern University’s Oceanographic Center (NSUOC) in Dania Beach, Florida.
Where I work
Since completing my doctoral degree in early 2014, I have been working as a postdoctoral research scientist at the Save Our Seas Shark Research Center. My lab is housed in the new 8,000-square-metre Center of Excellence for Coral Reef Ecosystem Research building on the NSUOC campus. Designed with marine research in mind, the building has state-of-the-art laboratory facilities, filtered sea water available to all labs, and a land-based coral nursery and other large salt-water tanks. Since conservation is an important aspect of the research being done at the NSUOC, our building has many environmentally friendly components. These include an air-conditioning system driven by ice that is frozen at night to alleviate the day’s tropical heat; a rain-catchment system for freshwater needs; and the efficient placement of windows to provide natural light while minimising heat gain. The conservation biology and genetics lab overlooks the semi-tropical Atlantic Ocean, with beautiful views of the ocean, the intra-coastal waterway and downtown Fort Lauderdale. Our marina is just minutes away from the open waters of the Atlantic, providing quick and easy access for all types of field studies.
What I do
I am a genetics nerd through and through! I do enjoy occasional field work to help my colleagues tag sharks or, better yet, a quick dive with sharks. However, I am soon driven to return to the lab or my computer to see what new information I can glean from my latest experiments. Our lab has been fortunate to receive large numbers of samples from generous collaborators around the world. These samples are usually small fin clips, which we carefully catalogue and store. I extract DNA from them and use one or more genetic loci (genes or specific regions of DNA) to evaluate different aspects of the secret lives of sharks.
Using standard population genetic techniques, I can begin to answer interesting questions about the molecular ecology of different species. For example, I typically start by looking at the amount of genetic diversity present within a species. Genetic diversity can provide an idea of the genetic health of the species. It can also be used to estimate effective population sizes in the past, which provide a general target for rebuilding overfished populations. Next I investigate whether there are genetic differences between geographic regions. If there are, there’s a good chance I can develop DNA-based forensic tests to establish a shark’s geographic origin. Such tests can be extremely useful in enforcing fishing and international trade restrictions, as well as in monitoring the numbers of sharks harvested in various regions.
Analysing shark mating systems is another interesting aspect of my work. Observations of sharks mating in the wild are extremely rare, which makes it almost impossible to discern the frequency of multiple mating based only on observation. However, when samples from a mother and her pups are available, I can estimate the number of males that sired the pups in the litter. Multiple paternity within litters can increase genetic diversity, which in turn can increase the natural resilience of the species. These and similar studies are helping us to better understand the biology and natural history of many shark species, and can provide important information to help manage and conserve these fascinating animals.